不同林下紫茎泽兰根部土壤营养成分比较

Comparison of the root soil nutrients of crofton weed in different forests

以有紫茎泽兰生长的青杠树林和松树林下的植株根部土壤为研究对象,测定两种土壤的全氮、铵态氮、全磷、速效磷、全钾、速效钾各营养成分含量,以探究同一生境下松树林下紫茎泽兰的生长数量远大于青杠树林下的原因。经过对两种土壤以上6个指标的测定分析,结果表明:土壤全氮、速效磷、速效钾含量青杠树林均高于松树林,而土壤全磷、全钾含量青杠树林则低于松树林,两种土壤铵态氮含量接近。因此,我们得出在松树林下的紫茎泽兰生长量较多而在青杠树林下较少的原因可能是:有紫茎泽兰生长的青杠树林土壤的全氮、速效磷、速效钾含量均高于相同生境的松树林土壤,这些土壤营养成分对紫茎泽兰的种群密度和入侵程度没有促进作用;而有紫茎泽兰生长的青杠树林土壤的全磷、全钾含量低于相同生境的松树林土壤,全磷、全钾对紫茎泽兰的种群密度和入侵程度有促进作用,说明紫茎泽兰适宜生长在全磷、全钾含量较高的土壤上。

To address the reason why the number and the density of crofion weed in the soils of pine forests are bigger than those in the Cyclobalanopsis trees under the same environment, the contents of total nitrogen, ammonium nitrogen, total phosphorus, available phosphorus, total potassium and available potassium in the two soils samples are investigated. The results show that the contents of soil total nitrogen, available phosphorus and available potassium in the soils from Cyclobalanopsis trees are higher than those from the pine forests, whereas the contents of soil total phosphorus, total potassium of the former are lower than those of the latter. There is no difference of the ammonium nitrogen content between them. The possible reason for the differences in the number and the density of crofton weed between these two types of soils is that the differences in the contents of total phosphorus and total potassium. Specifically, high contents of total phosphorus and total potassium in the pine forests soils would promote population density and invasion of crofton weed and are more suitable for the growth of erofton weed.